The present invention relates to tools for applying connectors and, more particularly, to an automatic tool for joining wires using wire joints.
Common electrical connectors for electrically and mechanically joining the stripped ends of insulated wires include wire joints, wire nuts and butt splice connectors. A wire joint includes a crimpable metallic ferrule retained in one end of an insulative housing with a skirt end of the housing extending therefrom for receiving the wires and directing them into the ferrule. A wire nut has a similar housing but uses a metallic element having an internal screw thread defining an opening of decreasing diameter. A butt splice comprises an elongate crimpable barrel and a housing having skirt portions extending from each end of the barrel.
The use of a wire joint is often preferable. For example, with respect to a butt splice connector, the wire joint requires only a single crimp, can accommodate a greater range of wire sizes and a greater number of wires, and requires less space since the wires extend unidirectionally from the joint. The wire joint also offers advantages over the wire nut in that the joint is typically less expensive, can be installed faster, offers a permanent connection, and does not require user judgement to avoid under or over tightening.
The typical method of applying wire joints includes the step of orienting a joint and placing it in the jaws of a pliers-type crimping tool. While holding the tool handles under slight pressure, the operator inserts the wires into the ferrule and squeezes the handles until the ferrule is crimped. It will be appreciated that iterative application of a number of joints becomes tedious and may result in discomfort to the user's hand.
A wire nut installation tool has been proposed for automatically applying wire nuts to the stripped ends of two or more wires. Of course, the connection provided by such a tool is not permanent and operator decision is required to set the torque applied to the wire nut. Additionally, this tool relies on the force of gravity to move the wire nuts into position for application. Thus the tool must be properly oriented to operate.